Ion channelling Rutherford backscattering spectrometry structural characterization of CdS/CdTe heterostructures

We report on the structural characterization by ion channelling Rutherford backscattering spectrometry (RBS) of thin (less than 3 μm) CdS epitaxial layers grown on {111}A-oriented CdTe substrates by chemical vapour deposition. The overall crystalline quality of the present epilayers has been studied as a function of their thickness. Also, the occurrence of single crystal growth vs. highly textured polycrystalline growth has been checked by studying channelling angular dips at different 4 He + beam energies. The CdS epilayers turned out to be essentially single crystalline, although the present RBS measurements show that extended defects are contained in the layers and at the CdS/CdTe interfaces. The dechannelling beam energy dependence allows us to identify these defects as stacking faults, whose concentration profile in the epilayers is reported.